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                                                                   Exhibit 10.35


                       THIRD AMENDMENT TO CREDIT AGREEMENT


      THIS THIRD AMENDMENT TO CREDIT AGREEMENT (this "Amendment") is entered
into as of September 29, 2004, by and between FAIR ISAAC CORPORATION (FORMERLY
KNOWN AS FAIR, ISAAC AND COMPANY, INCORPORATED), a Delaware corporation
("Borrower"), and WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank").


                                    RECITALS

      WHEREAS, Borrower is currently indebted to Bank pursuant to the terms and
conditions of that certain Credit Agreement between Borrower and Bank dated as
of November 1, 2002, as amended from time to time ("Credit Agreement").

      WHEREAS, Bank and Borrower have agreed to certain changes in the terms and
conditions set forth in the Credit Agreement and have agreed to amend the Credit
Agreement to reflect said changes.

      NOW, THEREFORE, for valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto agree that the Credit
Agreement shall be amended as follows:

      1. Section 4.8 is hereby deleted in its entirety, without substitution.

      2. Section 4.9 (a) is hereby deleted in its entirety, and the following
substituted therefor:

                  "(a) Total Funded Debt to EBITDA not greater than 2.0 to 1.0
            as of each fiscal quarter end, determined on a rolling four-quarter
            basis, with "Funded Debt" defined as the sum of all obligations for
            borrowed money (including subordinated debt) plus all capital lease
            obligations, and with "EBITDA" defined as net profit before tax plus
            interest expense (net of capitalized interest expense), depreciation
            expense and amortization expense."

      3. Section 5.7 is hereby deleted in its entirety, without substitution.

      4. Except as specifically provided herein, all terms and conditions of the
Credit Agreement remain in full force and effect, without waiver or
modification. All terms defined in the Credit Agreement shall have the same
meaning when used in this Amendment. This Amendment and the Credit Agreement
shall be read together, as one document.

      5. Borrower hereby remakes all representations and warranties contained in
the Credit Agreement and reaffirms all covenants set forth therein. Borrower
further certifies that as of the date of this Amendment there exists no Event of
Default as defined in the Credit Agreement, nor any condition, act or event
which with the giving of notice or the passage of time or both would constitute
any such Event of Default.


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      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed as of the day and year first written above.

                                          WELLS FARGO BANK,
FAIR ISAAC CORPORATION                      NATIONAL ASSOCIATION

By:  /s/ CHARLES M. OSBORNE               By:  /s/ DONALD GREEN
    -----------------------                   -----------------
                                                Donald Green
Title:  Chief Financial Officer                 Vice President



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